Biocompatibility testing of restorative materials influencing dentin and pulp

AbstractA comparative study was carried out using 27 healthy human bicuspids that had been extracted for orthodontic reasons from adolescents 11–14 years old. A microphotometrical analysis of buccal and lingual odontoblast layer thickness was performed using the SAMBA 2000 system and the results were submitted to statistical comparison. The buccal odontoblast layer (BOL) was found to be thicker than the lingual odontoblast layer (LOL). These results were independent of age, sex, and tooth position in the dental arch. Moreover, a strong relationship existed between the layer thicknesses as linear function on a logarithmic scale. Standards for the evaluation of pulp–dentin biocompatibility are based essentially upon qualitative or semiquantitative histological criteria. A method of quantitative evaluation based upon microphotometrical measurements of the thickness of the buccal odontoblast layer, considered variable, and the lingual odontoblast layer, considered stable, was applied to coronal filling materials that had previously been tested by a classic method. Seventy bicuspids extracted from adolescents 11–14 years of age whose class‐V cavities had been filled in situ with one of four restorative materials, and whose residual dentin thickness was less than 750 μm, were divided into two groups: an intermediate‐term group (A) and a long‐term group (B); both groups were subdivided into four experimental series as a function of test materials. A microphotometrical analysis was carried out using an automatic scanning system (SAMBA 2000) for the quantification of buccal and lingual odontoblast layer thicknesses. The results confirmed that due to the stability of the LOL thickness it may legitimately be used as reference in the study of the analogous BOL thickness. The BOL variations seemed proportional to the biocompatibility of the material tested. The quantitative results obtained should provide an accurate comparison of the materials at a given period of observation and substantiate a follow‐up study of the evolution of biocompatibility. © 1993 John Wiley & Sons, Inc.